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  • Articles: DFG German National Licenses  (35)
  • 1990-1994  (10)
  • 1975-1979  (14)
  • 1970-1974  (11)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 24 (1975), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Approximately 80 per cent of tyrosine hydroxylase activity in bovine mandibular nerve and rabbit sciatic nerve was soluble, and the rest of the activity was particle-bound. The soluble enzyme in bovine mandibular nerve was isolated by ammonium sulphate fractionation (25–35 per cent saturation). The enzyme had a pH optimum at 5·9 in Tris-acetate buffer, and at 6·5 in Tris-HCl or phosphate buffer. The enzyme required a tetrahydropteridine cofactor. Km values toward various tetrahydropteridines such as l-erythro-tetrahydrobiopterin (a probable natural cofactor), 2-amino-4-hydroxy-6-methyltetrahydropteridine, and 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine were 2 × 10−5m, 5 × 10−5m and 4 × 10−4m, respectively. The Km value for tyrosine at 1 × 10−3m-2-amino-4-hydroxy-6-methyltetrahydropteridine as a cofactor was 5 × 10−5m. The enzyme activity was markedly stimulated with Fe2+ or catalase, but Fe2+ gave higher activity. The activity was inhibited with α, α′-dipyridyl, l-α-methyl-p-tyrosine, and various catecholamines. Among catecholamines, dopamine was the most potent inhibitor. l-5-Hydroxytryptophan was an inhibitor as potent as dopamine. Neither d-5-hydroxytryptophan nor 5-hydroxytryptamine inhibited the enzyme. The inhibition by l-5-hydroxytryptophan was partially competitive with tetrahydrobiopterin at concentrations higher than 9 × 10−5m, and partially uncompetitive at concentrations lower than 9 × 10−5m. The addition of heparin or lysolecithin did not affect enzyme activity with tetrahydrobiopterin as cofactor.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 30 (1978), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Dopamine-β-hydroxylase (DBH) activity in serum was decreased significantly in schizophrenic patients (16.17 ± 12.60 μmol/min/1 of serum, mean ± S.D., n = 149) when compared with that of normal controls (42.53 ± 30.94 μmol/min/1 of serum, mean ± S.D., n= 153) and neurotic patients. Long duration of disease did not cause any significant changes in serum DBH activity except a tendency for increase in patients of lodger than 18 years duration. We also examined the possibility that the serum DBH deficiency in the schizophrenic group was an artifact of treatment with antipsychotic drugs, especially phenothiazines. No significant difference was observed between the patients treated with the drugs and the patients not receiving the drugs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 24 (1975), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 18 (1971), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Approximately 80 per cent of tyrosine hydroxylase activity in bovine caudate nucleus was particle-bound. The rest of the activity was found in the soluble fraction. The enzyme activity in crude tissue preparations was inhibited, probably by the presence of endogenous inhibitors. Dilution of crude tissue preparations such as the crude mitochondrial fraction caused an increase in the specific activity. The particle-bound enzyme was solubilized by incubation with trypsin. The presence of deoxycholate increased the degree of solubilization. The activity of the solubilized enzyme from the washed particles was also inhibited, but the subsequent purification by ammonium sulphate could eliminate the inhibition. The solubilized enzyme was partially purified by ammonium sulphate fractionation and Sephadex G-150 chromatography. A tetrahydropteridine and ferrous ion were required as cofactors for the partially purified enzyme. Among various divalent cations, only ferrous ion could activate the partially purified enzyme. The enzyme was inhibited by L-α-methyl-p-tyrosine and catecholamines such as dopamine. The optimum pH was found between 5.5 and 6.0. Km values toward tyrosine, 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine and Fe2+, were approximately 5 × 10−5 M, 1 × 10−4 M and 4 × 10−4 M, respectively.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 29 (1977), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 18 (1971), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Monoamine oxidase was purified approximately 40-fold from beef brain mitochondria. The purification procedure involved extraction with a non-ionic detergent (Nonion NS-210) after heat treatment, ammonium sulphate fractionation, chromatographies on DEAE-cellulose and Sepharose 6B, and a continuous flow electrophoresis. A major component (enzyme 1) with a higher specific activity and a minor component (enzyme 2) with a lower specific activity were separated. Properties of both enzymes towards kynuramine including pH-optimum and Km values were similar, but the enzyme 1 had the higher specific activity towards tyramine whereas that of enzyme 2 was towards normetane-phrine. Fluorescence spectra indicated that the enzyme 1 is a flavoprotein. Copper was not detected, and copper chelating agents did not inhibit the enzyme. p-Chloromercuribenzoate and JV-ethylmaleimide inhibited the enzyme, indicating the presence of the essential SH-groups.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1463
    Keywords: Tyrosine hydroxylase ; aromatic L-amino acid decarboxylase ; Parkinson's disease ; schizophrenia ; RT-PCR ; mRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using the reverse transcription-polymerase chain reaction (RT-PCR), we developed a sensitive and quantitative method to detect all four types of human tyrosine hydroxylase (TH) mRNAs in the human brain (substantia nigra). All four types of TH mRNAs were found in the substantia nigra in the control brains examined, and the ratio of type-1, type-2, type-3, and type-4 mRNAs to the total amount of TH was 45, 52, 1.4, and 2.1%, respectively. The average amount of total TH mRNA in the normal brain (substantia nigra) was 5.5 amol of TH mRNA per μg of total RNA. The ratios of four TH isoforms were not altered significantly in Parkinson's disease or schizophrenia. Further we measured the relative amount of aromatic L-amino acid decarboxylase (AADC) and β-actin mRNAs in the brain samples. TH and AADC mRNAs were highly correlated in the control cases. We found that parkinsonian brains had very low levels of all four TH isoforms and AADC mRNAs in the substantia nigra compared with control brains, while no significant differences were found between schizophrenic brains and normal ones. Since the decrease in AADC mRNA was comparable to that in TH mRNA, the alteration of TH in Parkinson's disease would not be a primary event, but it would reflect the degeneration of dopaminergic neurons in the substantia nigra. This is the first reported measurement of mRNA contents of TH isoforms and AADC in Parkinson's disease and schizophrenia.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1435-1463
    Keywords: Fetal brain ; 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine ; 1-methyl-4-phenylpyridinium ion ; catecholamine ; indoleamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of a dopaminergic neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the amounts of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were examined in the whole brains of fetal mice and maternal mice after its administration to pregnant mice. DA and DOPAC concentrations were decreased significantly in both the fetal and maternal brains. At 3 hr after injection, reduction of the DOPAC concentration was more marked than that of DA in both the fetal and maternal brains. Increase of 5-HT concentration was observed until 12 hr after injection in the fetal brains and 6 hr in the maternal brains. These results indicate that 1-methyl-4-phenyl-pyridinium ion (MPP+) and MPTP affect the levels of catechol- and indoleamines in the brain of premature stage as well as in the mature brain.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1435-1463
    Keywords: Suprachiasmatic nucleus ; microdialysis ; methamphetamine ; serotonin ; 5-hydroxyindoleacetic acid ; circadian pacemaker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The suprachiasmatic nucleus (SCN) has been identified as a major circadian pacemaker. Methamphetamine has been shown to modify the behavior of circadian rhythms. We detected extracellular serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the SCN in freely moving rats, using a microdialysis method, to investigate biochemical effects of methamphetamine in the SCN. Methamphetamine infusion into the SCN dose-dependently increased extracellular 5-HT and decreased extracellular 5-HIAA.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 28 (1972), S. 905-906 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Es wird gezeigt, dass die Dopamin-β-Hydroxylase-Aktivität im Serum bei spontan hypertonischen Ratten im Vergleich zu normotonen Kontrollen nicht verändert ist.
    Type of Medium: Electronic Resource
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